The map compares the GDP of U.S. states with other the national GDPs of other nations.

"America’s largest state economy is California, which produced $2.003 trillion of economic output in 2012, just slightly below Italy’s GDP in the same year of $2.013 trillion," Perry notes. "In 2012, California would have been tied with Italy as the 9th largest economy in the world. And California’s population is only 38 million compared to Italy’s population of 61 million, which means California produces the same economic output as Italy with 37% fewer people. That’s a testament to the superior, world-class productivity of the American worker."

With 4.4% of the world's population, the U.S. produced 22.3% of world GDP in 2012. Not bad.